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| Associated Press

FILE - In this Jan. 5, 2012 file photo, man-made snow coats a ski run next to barren ground under a chairlift at Shawnee Peak ski area in Bridgton, Maine. Scientists point to both scant recent snowfall in parts of the country and this month's whopper of a Northeast blizzard as potential global warming signs. It may seem like a contradiction, but the explanation lies in atmospheric physics. (AP Photo/Robert F. Bukaty) / AP

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WASHINGTON — With scant snowfall and barren ski slopes in parts of the Midwest and Northeast the past couple of years, some scientists have pointed to global warming as the culprit.

Then when a whopper of a blizzard smacked the Northeast with more than 2 feet of snow in some places earlier this month, some of the same people again blamed global warming.

How can that be? It’s been a joke among skeptics, pointing to what seems to be a brazen contradiction.

But the answer lies in atmospheric physics. A warmer atmosphere can hold, and dump, more moisture, snow experts say. And two soon-to-be-published studies demonstrate how there can be more giant blizzards yet less snow overall each year. Projections are that that’s likely to continue with man-made global warming.

Consider:

— The United States has been walloped by twice as many of the most extreme snowstorms in the past 50 years than in the previous 60 years, according to an upcoming study on extreme weather by leading federal and university climate scientists. This also fits with a dramatic upward trend in extreme winter precipitation — both rain and snow — in the Northeastern U.S. charted by the National Climatic Data Center.

— Yet the Global Snow Lab at Rutgers University says that spring snow cover in the Northern Hemisphere has shrunk on average by 1 million square miles in the last 45 years.

— And an upcoming study in the Journal of Climate says computer models predict annual global snowfall to shrink by more than a foot in the next 50 years. The study’s author said most people live in parts of the United States that are likely to see annual snowfall drop between 30 and 70 percent by the end of the century.

“Shorter snow season, less snow overall, but the occasional knockout punch,” Princeton University climate scientist Michael Oppenheimer said. “That’s the new world we live in.”

Ten climate scientists say the idea of less snow and more blizzards makes sense: A warmer world is likely to decrease the overall amount of snow falling each year and shrink snow season. But when it is cold enough for a snowstorm to hit, the slightly warmer air is often carrying more moisture, producing potentially historic blizzards.

Just look at the last few years in the Northeast.

The Rutgers snow lab says this January saw the sixth-widest snow cover in the Northern Hemisphere; the United States had an above average snow cover for the last few months. But that’s a misleading statistic, Robinson said, because even though more ground is covered by snow, it’s covered by less snow.

And when those big storms finally hit, there is more than just added moisture in the air, there’s extra moisture coming from the warm ocean, Robinson and Oppenheimer said. And the air is full of energy and unstable, allowing storms to lift yet more moisture up to colder levels. That generates more intense rates of snowfall, Robinson said.

“If you can tap that moisture and you have that fortuitous collision of moist air and below freezing temperatures, you can pop some big storms,” Robinson said.